Fan Out Wafer Level Packaging (FOWLP) is a wafer-level packaging technique which allows the production of an embedded component package having multiple dies and passive components. The technique provides a package with a reduced footprint and an increased area for solder ball connection.
The embedded component package is formed by placing one or more electronic components, e.g., active components and passive components, onto an adhesive carrier with the electronic component terminals, e.g., bond pads, facing the carrier. The electronic components are then overmolded with a dielectric material, e.g., epoxy mold compound, to form an embedded component substrate. The embedded component substrate is a composite of the electronic components embedded within the dielectric material. The embedded component substrate is removed from the carrier.
To allow electrical interconnection with the embedded electronic components, a dielectric layer is blanket formed across the entire embedded component substrate and covers the embedded electronic components. Openings are formed in the dielectric layer to expose the terminals of the embedded electronic components. A metal layer is formed on the dielectric layer and extends through the openings to define circuitry to redistribute the pattern of terminals of the embedded electronic components. The process of forming dielectric layers and metal layers, sometimes called redistribution layer (RDL) dielectric layers and RDL metal layers, is repeated depending upon the redistribution desired.
To smooth the unevenness of the embedded component substrate, the thickness of the RDL dielectric layer applied to the embedded component substrate is relatively thick. The large thickness of the RDL dielectric layer prevents formation of high aspect ratio openings within the RDL dielectric layer and fine pitch RDL metal layers.
The present invention is illustrated by way of example and is not limited by the accompanying figures, in which like references indicate similar elements. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.